One hundred observers identified by name fifty blue, green, white, and purple test colors. Small areas and low illuminances were used to simulate conditions under which signal lights must be recognized. The results are expressed as chromaticity zones within which the test colors were assigned a given color name with various degrees of certainty. Large individual differences in color naming were found. Variability due to intensity and viewing distance is also demonstrated. The data can be applied to the specification of boundaries for colored signals.
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Frequencies with which each color name was applied to each test color at “High” illuminance by 100 observers.
Color number
“Red”
“Yellow”
“Green”
“Blue”
“Purple”
“White”
1
5
17
78
2
1
3
32
64
3
1
2
47
50
4
1
17
64
18
5
29
61
10
6
47
49
4
7
78
22
8
96
4
9
99
1
10
3
1
19
76
1
11
1
2
25
72
12
1
7
58
34
13
17
65
17
1
14
1
43
51
5
15
69
29
2
16
92
8
17
98
2
18
2
11
83
4
19
1
1
16
78
4
20
1
4
49
46
21
10
63
24
3
22
55
39
2
4
23
66
32
2
24
86
13
1
25
1
95
4
26
1
3
11
77
8
27
1
3
12
69
15
28
2
45
35
18
29
1
14
53
4
28
30
1
47
33
3
16
31
1
80
7
12
32
1
92
2
5
33
4
3
1
5
78
9
34
2
3
2
11
50
32
35
3
2
20
27
48
36
2
19
24
4
51
37
8
50
8
34
38
6
73
3
18
39
12
10
6
48
24
40
2
5
1
8
33
51
41
9
1
7
7
76
42
7
29
8
1
55
43
19
45
3
1
32
44
7
22
4
34
33
45
2
14
1
7
9
67
46
15
2
2
1
80
47
30
32
1
1
36
48
4
35
1
8
52
49
25
1
1
73
50
1
48
51
Table V
Frequencies with which each color name was applied to each test color at “Low” illuminance by 100 observers.
Color number
“Red”
“Yellow”
“Green”
“Blue”
“Purple”
“White”
1
4
3
23
69
1
2
1
6
36
56
1
3
1
16
51
32
4
29
61
10
5
41
54
5
6
64
34
1
1
7
85
15
8
96
4
9
94
5
1
10
2
4
20
74
11
1
8
40
51
12
18
64
18
13
43
51
6
14
1
56
36
3
4
15
76
22
2
16
94
6
17
97
3
18
1
1
2
14
76
6
19
2
7
26
62
3
20
15
48
35
2
21
1
35
51
12
1
22
54
44
2
23
1
66
30
2
1
24
83
17
25
94
6
26
1
4
4
6
71
14
27
4
16
57
23
28
2
11
47
26
14
29
1
35
44
15
5
30
1
55
32
1
11
31
76
19
5
32
1
86
12
1
33
4
5
1
11
59
20
34
2
5
4
12
42
35
35
1
1
14
22
25
37
36
4
28
35
3
30
37
2
52
19
1
26
38
2
71
12
15
39
11
18
1
4
33
33
40
11
4
12
20
53
41
1
13
5
8
12
61
42
7
27
10
2
54
43
10
49
11
30
44
8
24
1
2
24
41
45
2
25
1
1
11
60
46
1
23
2
3
71
47
20
17
63
48
7
42
1
6
44
49
3
31
6
3
57
50
58
1
41
Table VI
Comparison of the present data with those of Holmes. Conditions matching most closely in illuminance level and visual angle have been chosen from the two investigations (see text).
Contours have same general orientation; present data show better identification of desaturated greens.
visual angle
7′
aver., 6.3′
illuminance
75.4 mile-c
aver., 67.2 mile-c
obs./color
6×3
50×1
adapted to
dark
0.001 ft-L
“Blue”
series
Id: Fig. 9
“Low,” back rows
Present data show much better identification of desaturated blues; Holmes gives no 50% contour.
visual angle
2.2′
aver., 4.4′
illuminance
7.5 mile-c
aver., 3.5 mile-c
obs./color
50×1
50×1
adapted to
dark
0.001 ft-L
series
Va: Fig. 15
“Low,” back rows
Holmes’ light-adapted observers consistently identified more blues, extending the blue area farther toward green and white.
visual angle
2.2′
aver., 4.4′
illuminance
7.5 mile-c
aver., 3.5 mile-c
obs./color
4×3
50×1
adapted to
about 1 ft-L
0.001 ft-L
“Purple”
No overlap of areas studied.
“White”
series
Ie: Fig. 10
“High,” front rows
Same blue limit; present data show smaller white area, probably different orientation.
visual angle
7′
aver., 6.3′
illuminance
75.4 mile-c
aver., 84.9 mile-c
obs./color
6×3
50×1
adapted to
dark
0.001 ft-L
The number of observations per color is given as (number of observers)×(repetitions); Holmes used 256 colors, Halsey 50. In both cases the permissible responses were R, Y, G, B, W, P and the duration of a test color was 2 sec. Viewing distances were similar.
Frequencies with which each color name was applied to each test color at “High” illuminance by 100 observers.
Color number
“Red”
“Yellow”
“Green”
“Blue”
“Purple”
“White”
1
5
17
78
2
1
3
32
64
3
1
2
47
50
4
1
17
64
18
5
29
61
10
6
47
49
4
7
78
22
8
96
4
9
99
1
10
3
1
19
76
1
11
1
2
25
72
12
1
7
58
34
13
17
65
17
1
14
1
43
51
5
15
69
29
2
16
92
8
17
98
2
18
2
11
83
4
19
1
1
16
78
4
20
1
4
49
46
21
10
63
24
3
22
55
39
2
4
23
66
32
2
24
86
13
1
25
1
95
4
26
1
3
11
77
8
27
1
3
12
69
15
28
2
45
35
18
29
1
14
53
4
28
30
1
47
33
3
16
31
1
80
7
12
32
1
92
2
5
33
4
3
1
5
78
9
34
2
3
2
11
50
32
35
3
2
20
27
48
36
2
19
24
4
51
37
8
50
8
34
38
6
73
3
18
39
12
10
6
48
24
40
2
5
1
8
33
51
41
9
1
7
7
76
42
7
29
8
1
55
43
19
45
3
1
32
44
7
22
4
34
33
45
2
14
1
7
9
67
46
15
2
2
1
80
47
30
32
1
1
36
48
4
35
1
8
52
49
25
1
1
73
50
1
48
51
Table V
Frequencies with which each color name was applied to each test color at “Low” illuminance by 100 observers.
Color number
“Red”
“Yellow”
“Green”
“Blue”
“Purple”
“White”
1
4
3
23
69
1
2
1
6
36
56
1
3
1
16
51
32
4
29
61
10
5
41
54
5
6
64
34
1
1
7
85
15
8
96
4
9
94
5
1
10
2
4
20
74
11
1
8
40
51
12
18
64
18
13
43
51
6
14
1
56
36
3
4
15
76
22
2
16
94
6
17
97
3
18
1
1
2
14
76
6
19
2
7
26
62
3
20
15
48
35
2
21
1
35
51
12
1
22
54
44
2
23
1
66
30
2
1
24
83
17
25
94
6
26
1
4
4
6
71
14
27
4
16
57
23
28
2
11
47
26
14
29
1
35
44
15
5
30
1
55
32
1
11
31
76
19
5
32
1
86
12
1
33
4
5
1
11
59
20
34
2
5
4
12
42
35
35
1
1
14
22
25
37
36
4
28
35
3
30
37
2
52
19
1
26
38
2
71
12
15
39
11
18
1
4
33
33
40
11
4
12
20
53
41
1
13
5
8
12
61
42
7
27
10
2
54
43
10
49
11
30
44
8
24
1
2
24
41
45
2
25
1
1
11
60
46
1
23
2
3
71
47
20
17
63
48
7
42
1
6
44
49
3
31
6
3
57
50
58
1
41
Table VI
Comparison of the present data with those of Holmes. Conditions matching most closely in illuminance level and visual angle have been chosen from the two investigations (see text).
Contours have same general orientation; present data show better identification of desaturated greens.
visual angle
7′
aver., 6.3′
illuminance
75.4 mile-c
aver., 67.2 mile-c
obs./color
6×3
50×1
adapted to
dark
0.001 ft-L
“Blue”
series
Id: Fig. 9
“Low,” back rows
Present data show much better identification of desaturated blues; Holmes gives no 50% contour.
visual angle
2.2′
aver., 4.4′
illuminance
7.5 mile-c
aver., 3.5 mile-c
obs./color
50×1
50×1
adapted to
dark
0.001 ft-L
series
Va: Fig. 15
“Low,” back rows
Holmes’ light-adapted observers consistently identified more blues, extending the blue area farther toward green and white.
visual angle
2.2′
aver., 4.4′
illuminance
7.5 mile-c
aver., 3.5 mile-c
obs./color
4×3
50×1
adapted to
about 1 ft-L
0.001 ft-L
“Purple”
No overlap of areas studied.
“White”
series
Ie: Fig. 10
“High,” front rows
Same blue limit; present data show smaller white area, probably different orientation.
visual angle
7′
aver., 6.3′
illuminance
75.4 mile-c
aver., 84.9 mile-c
obs./color
6×3
50×1
adapted to
dark
0.001 ft-L
The number of observations per color is given as (number of observers)×(repetitions); Holmes used 256 colors, Halsey 50. In both cases the permissible responses were R, Y, G, B, W, P and the duration of a test color was 2 sec. Viewing distances were similar.